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1) Urgent metabolic intervention decreases mortality of LCHAD-deficient patients, but the prognosis is still uncertain. 2) Emergent metabolic reporting and service are crucial also for the survival of neonates detected by NBS. 3) The nationwide selective screening appeared efficient in LCHADD detection in the country. 4) Transient mild hyperphenylalaninaemia may occur in LCHAD-deficient newborns.

Objectives Together with the lysosomal storage diseases, NGLY1 deficiency is a congenital disorder of deglycosylation (NGLY1‐CDDG). Since the first report in 2012, 26 patients have been described. All but one were diagnosed by exome or genome sequencing; the remaining one was identified by finding an increased concentration of an urinary marker. The aim of this study was to describe the clinical, biochemical, and molecular features of the first Polish patient diagnosed with NGLY1‐CDDG, to provide an overview of the literature and to propose a diagnostic algorithm. Results A Polish patient presented with global developmental delay, hyperkinetic movement disorder, stagnation of head growth, hypolacrimia, elevated serum transaminases, and hypolipidemia in infancy. Whole exome sequencing revealed two heterozygous nonsense variants in the NGLY1 gene (a novel and an unreported). Literature review revealed global developmental disability in all reported patients, and hyperkinetic movements as well as alacrima/hypolacrima in nearly all. Conclusions NGLY1‐CDDG should be considered in patients with developmental disability associated with a hyperkinetic movement disorder and alacrimia/hypolacrima. Absence of the latter two symptoms does not rule out this diagnosis.

Introduction The incidence and prevalence of congenital disorders of glycosylation (CDG) have not been well established. The aim of the study was to evaluate the prevalence, incidence and genotypes of CDG patients diagnosed during the last 23 years in Poland (1997 – 30th October 2020). Material and methods The diagnosis was based on serum Tf IEF which is performed at The Children's Memorial Health Institute (CMHI) in Warsaw. Based on demographic data, the prevalence of CDG among the Polish population in 2020 as well as the birth prevalence of CDG from 1990 to 2020 were estimated. Results 39 patients (from 35 families) with molecularly confirmed CDG were diagnosed, including 17 (44%) patients (from 16 families) with PMM2-CDG. The c.422G > A, p.Arg141His and c.691G > A, p.Val231Met pathogenic missense variants were the most common identified PMM2 variants. Eleven other patients were diagnosed with CDG based on serum Tf IEF analysis only; the molecular analysis is pending. Ten CDG patients died, including 6 with PMM2-CDG, 1 with PGM1-CDG and 1 with DPAGT1-CDG. The prevalence of CDG in the Polish population was estimated at approximately 1 per million while that of PMM2 at 0.4 per million. The annual incidence of CDG was estimated at 0.013 per 100,000 people in 2020. Conclusions A low frequence of CDG in our study could be underestimated.

Background: Congenital disorders of glycosylation (CDG) result from defects in the synthesis of glycans and their attachment to proteins and lipids. Histologically, liver steatosis, fibrosis and cirrhosis have been reported in CDG. The aim of the study was to characterize the histopathological and ultrastructural liver changes in CDG patients hospitalized in our Institute, and to find the most characteristic features, as articles concerning the liver microscopic features in CDG are sparse. Methods: Out of 32 CDG patients diagnosed and followed-up in our Institute, the liver biopsy was performed in 4 of them, including 2 with MPI-CDG, 1 with SRD5A3-CDG, and 1 with PGM1-CDG, as a part of diagnostic process. In one patient, diagnosed post mortem with PMM2-CDG, the histopathological study comprised liver autopsy samples. Results: The most common histopathological liver finding was the presence of steatosis (4/5) of varying severity, the mixed macro-and microvesicular type as well as the foamy degeneration of hepatocytes. In two patients, liver steatosis was associated with fibrosis, stage 4 (cirrhosis) and 2 according to Batts and Ludwig classification, respectively. In two patients, besides steatosis, mild inflammatory infiltrates composed of lymphoid cells in portal tracts were observed. No correlation between the patient's age and histopathological features was observed.